Temperature dependent gas sensing properties of tin-doped zinc oxide films

Abstract

In this work, the temperature dependent gas sensing properties of tin-doped zinc oxide (ZnO:Sn) nanostructured films are investigated in detail. The two different contents of Sn in ZnO:Sn samples (0.1 and 0.4 at% Sn) and rapid thermal annealing (RTA) at 725 ºC were used, in order to find out the optimal conditions for the highest gas sensing properties, i.e. higher gas response, selectivity and lowest operating temperature. Generally, the Sn-doped ZnO nanostructured films showed high selectivity to volatile organic compounds (VOCs) vapors, such as ethanol, acetone, 2-propanol and n-butanol, compared to different reducing gases such as H2, NH3 and CH4. The optimal operating temperature for all films is 250 – 300 ºC and the optimal content of Sn is 0.4 at%. The asgrown films showed higher gas response compared to RTA treated ones. The gas sensing mechanism was proposed and discussed in detail.